A multipurpose gas burner includes a rear housing, a front housing, a pressure regulating device, a control device, a gas release device and an outer tube unit. The rear housing contains a conventional gas container and is provided with a press rod and an insert nozzle connected to a gas spout of the gas container. Upon pressing a push button, a lower slide seat will press against a piezo-electric device while an upper slide seat is relatively displaces to cause the press rod to press against the gas spout of the gas container to release fuel gas. The pressure regulating device regulates the pressure of the fuel gas and controls its outflow. The regulated fuel gas is ejected via a gas nozzle into the gas release device where it is mixed with air drawn in from the outside. The mixture is then ejected by a fire nozzle and is ignited by sparks generated by means of the piezo-electric device at the outer tube unit. A heating tube may be further fitted to the gas burner to form a heating device, and a soldering iron may be additionally fitted onto the heating tube for soldering purposes.